This invention relates to a process for preparing draw-textured polyester yarns and novel feed yarns suitable for use in such a process.
It has been suggested to produce permanently crimped textured yarns by drawing and false-twist texturing of undrawn polyester yarns melt-spun at a windup speed of about 3000 - 4000 yards per minute, as for example in U.S. Pat. Nos. 3,771,307 and 3,772,872.
According to these processes, it is possible to produce draw-textured yarns having good crimp properties superior to those of conventional textured yarns processed at similar twist levels and heat-setting temperatures at high productivity with low cost.
However, polyester feed yarns obtained by melt spinning at a speed of about 3000 - 4000 yards per minute have relatively poor stability during long periods of storage or transport, and significant deterioration and unevenness take place in the draw-texturing of such stored feed yarns. For example, the feed yarns, after storage for 20 days at 35.degree.C. or higher, are more susceptible to filament breakage and fluffs during the draw-texturing process, than freshly spun yarns. Furthermore, textured yarns obtained from said stored feed yarns are dyed more deeply or unevenly than those from as-spun yarns. In addition, it is necessary to exercise special caution in threading-up the yarn to the draw-texturing machine, because great shrinkage of said feed yarns takes place when they come into contact with the heater. And textured yarns obtained from such feed yarns have poor appearance and hand, since the feed yarns become highly deformed in their cross section during the draw-texturing process.
Additional prior art of possible interest includes the following:
U.S. Pat. No. 2,604,667, related to a high-speed process for melt-spinning polyethylene terephthalate material to produce as-spun fibers and yarns.
U.S. Pat. No. 2,604,689, related to a process for melt-spinning polyethylene terephthalate material to produce tenacious, resilient fibers and yarns.
U.S. Pat. Nos. 2,952,879; 3,091,510; and 3,549,597, related to processes for producing linear terephthalate polyesters which have the property of undergoing a spontaneous and irreversible extension in length when they are heated.
U.S. Pat. No. 3,563,892, related to a textile treating composition and lubricant useful for high-temperature drawing of polyester filaments.
U.S. Pat. No. 3,594,200, related to a textile finish composition for high-speed and high-temperature twisting processing.
British Pat. No. 746,992, related to the crimping of synthetic yarns by imparting to them a temporary high twist by means of a false-twisting device.
British Pat. No. 777,625, related to a process for producing bulky synthetic yarns by the use of a flase-twisting device and heat setting.
British Pat. No. 852,579, related to producing crimped synthetic linear polymer yarns by false-twisting and drawing the as-spur yarn simultaneously.
British Pat. No. 890,053, related to a process and apparatus for crimping synthetic yarn by false-twisting.
British Pat. No. 1,333,679 (German O.L. No. 2,116,502), related to false twist-crimped polyester yarns containing at least 80 mole % of ethylene terephthalate units.
French Pat. No. 2,001,980, related to improvements for the production of bulky synthetic yarns by false-twist crimping.
The publication "Faserforchung und Textiltechnik", 9 (1958), No. 6, Pages 226-231, related to the spinning of polycondensate fibers at high delivery speeds.
The publication " Faserforchung und Textiltechnik", 11 (1960), No. 7, Pages 312-319, related to the spinning and stretching of polycondensate filaments.
The publication "Textile Industries", March 1970, Pages 117-131, related to the state of textured yarn technology in Europe.
The publication "Chemiefasern/textil-industrie", September 1973, pages 818-821; October 1973, pages 964-975; and November 1973, pages 1109-1114; related to structural changes of polyester filaments during orientation and tempering.
The publication "Chemiefasern/textil-industrie", November 1973, pages 1067-1080, related to the status and development of stretch-texturing synthetic yarns.